I have following code in Pyhton:
# myFile.csv tend to looks like:
# 'a1', 'ふじさん', 'c1'
# 'a2', 'ふじさん', 'c2'
# 'a3', 'ふじさん', 'c3'
s = u"unicodeText" # unicodeText like, ふじさん بعدة أش 일본富士山Ölkələr
with codecs.open('myFile.csv', 'w+', 'utf-8') as f: # codecs open
f.write(s.encode('utf-8', 'ignore'))
I was using Vim to edit the code and using Vim to open "myFile.csv";
It can success display unicode text from terminal;
but not able to display unicode text from Excel, nor from browser;
My platform is osx
I don't know if is my configuration problem or actually I code it wrong way, if you any idea, please advise. Deeply appreciate!
change open to codecs.open.
Thanks for point out f.close(), deleted.
Excel (at least on Windows) likes a Unicode BOM at the start of a .csv file even with UTF-8. There is a codec for that, utf-8-sig.
Also, Python 3's normal open is all that is required and no need for f.close() in a with:
#coding:utf8
data = '''\
a1,ふじさん,c1
a2,ふじさん,c2
a3,ふじさん,c3
'''
with open('myFile.csv', 'w', encoding='utf-8-sig') as f:
f.write(data)
It seems you're trying to open the file in text mode (because you specify an encoding), but then you try to write binary data (because you encode the text before writing it to the file). You need to either open the file as binary and write encoded text, or open it as text and write text.
Furthermore, your attempt to open it as text isn't even working because you're passing utf-8 as the buffering parameter instead of the encoding parameter. See the open() documentation`.
But even if you did all that correctly, this still wouldn't really help you with an Excel file, because those have a complicated binary structure. I recommend you use something like the xlrd to read xls files and Xlswriter to write them.
Here is a simple example that should work for .csv:
with open('file.csv', 'w', encoding='utf-8') as fh:
fh.write('This >µ< is a unicode GREEK LETTER MU\n')
or alternatively
with open('file.csv', 'wb') as fh:
fh.write('This >µ< is a unicode GREEK LETTER MU\n'.encode('utf-8'))
codecs.open opens a wrapped reader/writer which will do encoding/decoding for you. So you do not need to encode your string for writing. You need to pass the 'ignore' parameter in your open call.
with open('myFile.csv', 'w+', 'utf-8', 'ignore') as f:
f.write(s)
Note that you do not need to call close as you use a with statement.
Original answer, scratch that:
Third parameter of open is buffering requiring an integer.
You should write pass the encoding like this:
with open('myFile.xls', 'w+', encoding='utf-8') as f:
Note that you open the file in text mode. No need to encode the string for writing.
Also your file mode 'w+' is a bit odd. I'm not sure, but I think it will truncate your file. If you want to append to the file you should use 'a' as mode.
Related
import csv
with open('thefile.csv', 'rb') as f:
data = list(csv.reader(f))
import collections
counter = collections.defaultdict(int)
for row in data:
counter[row[10]] += 1
with open('/pythonwork/thefile_subset11.csv', 'w') as outfile:
writer = csv.writer(outfile)
for row in data:
if counter[row[10]] >= 504:
writer.writerow(row)
This code reads thefile.csv, makes changes, and writes results to thefile_subset1.
However, when I open the resulting csv in Microsoft Excel, there is an extra blank line after each record!
Is there a way to make it not put an extra blank line?
The csv.writer module directly controls line endings and writes \r\n into the file directly. In Python 3 the file must be opened in untranslated text mode with the parameters 'w', newline='' (empty string) or it will write \r\r\n on Windows, where the default text mode will translate each \n into \r\n.
#!python3
with open('/pythonwork/thefile_subset11.csv', 'w', newline='') as outfile:
writer = csv.writer(outfile)
In Python 2, use binary mode to open outfile with mode 'wb' instead of 'w' to prevent Windows newline translation. Python 2 also has problems with Unicode and requires other workarounds to write non-ASCII text. See the Python 2 link below and the UnicodeReader and UnicodeWriter examples at the end of the page if you have to deal with writing Unicode strings to CSVs on Python 2, or look into the 3rd party unicodecsv module:
#!python2
with open('/pythonwork/thefile_subset11.csv', 'wb') as outfile:
writer = csv.writer(outfile)
Documentation Links
https://docs.python.org/3/library/csv.html#csv.writer
https://docs.python.org/2/library/csv.html#csv.writer
Opening the file in binary mode "wb" will not work in Python 3+. Or rather, you'd have to convert your data to binary before writing it. That's just a hassle.
Instead, you should keep it in text mode, but override the newline as empty. Like so:
with open('/pythonwork/thefile_subset11.csv', 'w', newline='') as outfile:
Note: It seems this is not the preferred solution because of how the extra line was being added on a Windows system. As stated in the python document:
If csvfile is a file object, it must be opened with the ‘b’ flag on platforms where that makes a difference.
Windows is one such platform where that makes a difference. While changing the line terminator as I described below may have fixed the problem, the problem could be avoided altogether by opening the file in binary mode. One might say this solution is more "elegent". "Fiddling" with the line terminator would have likely resulted in unportable code between systems in this case, where opening a file in binary mode on a unix system results in no effect. ie. it results in cross system compatible code.
From Python Docs:
On Windows, 'b' appended to the mode
opens the file in binary mode, so
there are also modes like 'rb', 'wb',
and 'r+b'. Python on Windows makes a
distinction between text and binary
files; the end-of-line characters in
text files are automatically altered
slightly when data is read or written.
This behind-the-scenes modification to
file data is fine for ASCII text
files, but it’ll corrupt binary data
like that in JPEG or EXE files. Be
very careful to use binary mode when
reading and writing such files. On
Unix, it doesn’t hurt to append a 'b'
to the mode, so you can use it
platform-independently for all binary
files.
Original:
As part of optional paramaters for the csv.writer if you are getting extra blank lines you may have to change the lineterminator (info here). Example below adapated from the python page csv docs. Change it from '\n' to whatever it should be. As this is just a stab in the dark at the problem this may or may not work, but it's my best guess.
>>> import csv
>>> spamWriter = csv.writer(open('eggs.csv', 'w'), lineterminator='\n')
>>> spamWriter.writerow(['Spam'] * 5 + ['Baked Beans'])
>>> spamWriter.writerow(['Spam', 'Lovely Spam', 'Wonderful Spam'])
The simple answer is that csv files should always be opened in binary mode whether for input or output, as otherwise on Windows there are problems with the line ending. Specifically on output the csv module will write \r\n (the standard CSV row terminator) and then (in text mode) the runtime will replace the \n by \r\n (the Windows standard line terminator) giving a result of \r\r\n.
Fiddling with the lineterminator is NOT the solution.
A lot of the other answers have become out of date in the ten years since the original question. For Python3, the answer is right in the documentation:
If csvfile is a file object, it should be opened with newline=''
The footnote explains in more detail:
If newline='' is not specified, newlines embedded inside quoted fields will not be interpreted correctly, and on platforms that use \r\n linendings on write an extra \r will be added. It should always be safe to specify newline='', since the csv module does its own (universal) newline handling.
Use the method defined below to write data to the CSV file.
open('outputFile.csv', 'a',newline='')
Just add an additional newline='' parameter inside the open method :
def writePhoneSpecsToCSV():
rowData=["field1", "field2"]
with open('outputFile.csv', 'a',newline='') as csv_file:
writer = csv.writer(csv_file)
writer.writerow(rowData)
This will write CSV rows without creating additional rows!
I'm writing this answer w.r.t. to python 3, as I've initially got the same problem.
I was supposed to get data from arduino using PySerial, and write them in a .csv file. Each reading in my case ended with '\r\n', so newline was always separating each line.
In my case, newline='' option didn't work. Because it showed some error like :
with open('op.csv', 'a',newline=' ') as csv_file:
ValueError: illegal newline value: ''
So it seemed that they don't accept omission of newline here.
Seeing one of the answers here only, I mentioned line terminator in the writer object, like,
writer = csv.writer(csv_file, delimiter=' ',lineterminator='\r')
and that worked for me for skipping the extra newlines.
with open(destPath+'\\'+csvXML, 'a+') as csvFile:
writer = csv.writer(csvFile, delimiter=';', lineterminator='\r')
writer.writerows(xmlList)
The "lineterminator='\r'" permit to pass to next row, without empty row between two.
Borrowing from this answer, it seems like the cleanest solution is to use io.TextIOWrapper. I managed to solve this problem for myself as follows:
from io import TextIOWrapper
...
with open(filename, 'wb') as csvfile, TextIOWrapper(csvfile, encoding='utf-8', newline='') as wrapper:
csvwriter = csv.writer(wrapper)
for data_row in data:
csvwriter.writerow(data_row)
The above answer is not compatible with Python 2. To have compatibility, I suppose one would simply need to wrap all the writing logic in an if block:
if sys.version_info < (3,):
# Python 2 way of handling CSVs
else:
# The above logic
I used writerow
def write_csv(writer, var1, var2, var3, var4):
"""
write four variables into a csv file
"""
writer.writerow([var1, var2, var3, var4])
numbers=set([1,2,3,4,5,6,7,2,4,6,8,10,12,14,16])
rules = list(permutations(numbers, 4))
#print(rules)
selection=[]
with open("count.csv", 'w',newline='') as csvfile:
writer = csv.writer(csvfile)
for rule in rules:
number1,number2,number3,number4=rule
if ((number1+number2+number3+number4)%5==0):
#print(rule)
selection.append(rule)
write_csv(writer,number1,number2,number3,number4)
When using Python 3 the empty lines can be avoid by using the codecs module. As stated in the documentation, files are opened in binary mode so no change of the newline kwarg is necessary. I was running into the same issue recently and that worked for me:
with codecs.open( csv_file, mode='w', encoding='utf-8') as out_csv:
csv_out_file = csv.DictWriter(out_csv)
import csv
with open('thefile.csv', 'rb') as f:
data = list(csv.reader(f))
import collections
counter = collections.defaultdict(int)
for row in data:
counter[row[10]] += 1
with open('/pythonwork/thefile_subset11.csv', 'w') as outfile:
writer = csv.writer(outfile)
for row in data:
if counter[row[10]] >= 504:
writer.writerow(row)
This code reads thefile.csv, makes changes, and writes results to thefile_subset1.
However, when I open the resulting csv in Microsoft Excel, there is an extra blank line after each record!
Is there a way to make it not put an extra blank line?
The csv.writer module directly controls line endings and writes \r\n into the file directly. In Python 3 the file must be opened in untranslated text mode with the parameters 'w', newline='' (empty string) or it will write \r\r\n on Windows, where the default text mode will translate each \n into \r\n.
#!python3
with open('/pythonwork/thefile_subset11.csv', 'w', newline='') as outfile:
writer = csv.writer(outfile)
In Python 2, use binary mode to open outfile with mode 'wb' instead of 'w' to prevent Windows newline translation. Python 2 also has problems with Unicode and requires other workarounds to write non-ASCII text. See the Python 2 link below and the UnicodeReader and UnicodeWriter examples at the end of the page if you have to deal with writing Unicode strings to CSVs on Python 2, or look into the 3rd party unicodecsv module:
#!python2
with open('/pythonwork/thefile_subset11.csv', 'wb') as outfile:
writer = csv.writer(outfile)
Documentation Links
https://docs.python.org/3/library/csv.html#csv.writer
https://docs.python.org/2/library/csv.html#csv.writer
Opening the file in binary mode "wb" will not work in Python 3+. Or rather, you'd have to convert your data to binary before writing it. That's just a hassle.
Instead, you should keep it in text mode, but override the newline as empty. Like so:
with open('/pythonwork/thefile_subset11.csv', 'w', newline='') as outfile:
Note: It seems this is not the preferred solution because of how the extra line was being added on a Windows system. As stated in the python document:
If csvfile is a file object, it must be opened with the ‘b’ flag on platforms where that makes a difference.
Windows is one such platform where that makes a difference. While changing the line terminator as I described below may have fixed the problem, the problem could be avoided altogether by opening the file in binary mode. One might say this solution is more "elegent". "Fiddling" with the line terminator would have likely resulted in unportable code between systems in this case, where opening a file in binary mode on a unix system results in no effect. ie. it results in cross system compatible code.
From Python Docs:
On Windows, 'b' appended to the mode
opens the file in binary mode, so
there are also modes like 'rb', 'wb',
and 'r+b'. Python on Windows makes a
distinction between text and binary
files; the end-of-line characters in
text files are automatically altered
slightly when data is read or written.
This behind-the-scenes modification to
file data is fine for ASCII text
files, but it’ll corrupt binary data
like that in JPEG or EXE files. Be
very careful to use binary mode when
reading and writing such files. On
Unix, it doesn’t hurt to append a 'b'
to the mode, so you can use it
platform-independently for all binary
files.
Original:
As part of optional paramaters for the csv.writer if you are getting extra blank lines you may have to change the lineterminator (info here). Example below adapated from the python page csv docs. Change it from '\n' to whatever it should be. As this is just a stab in the dark at the problem this may or may not work, but it's my best guess.
>>> import csv
>>> spamWriter = csv.writer(open('eggs.csv', 'w'), lineterminator='\n')
>>> spamWriter.writerow(['Spam'] * 5 + ['Baked Beans'])
>>> spamWriter.writerow(['Spam', 'Lovely Spam', 'Wonderful Spam'])
The simple answer is that csv files should always be opened in binary mode whether for input or output, as otherwise on Windows there are problems with the line ending. Specifically on output the csv module will write \r\n (the standard CSV row terminator) and then (in text mode) the runtime will replace the \n by \r\n (the Windows standard line terminator) giving a result of \r\r\n.
Fiddling with the lineterminator is NOT the solution.
A lot of the other answers have become out of date in the ten years since the original question. For Python3, the answer is right in the documentation:
If csvfile is a file object, it should be opened with newline=''
The footnote explains in more detail:
If newline='' is not specified, newlines embedded inside quoted fields will not be interpreted correctly, and on platforms that use \r\n linendings on write an extra \r will be added. It should always be safe to specify newline='', since the csv module does its own (universal) newline handling.
Use the method defined below to write data to the CSV file.
open('outputFile.csv', 'a',newline='')
Just add an additional newline='' parameter inside the open method :
def writePhoneSpecsToCSV():
rowData=["field1", "field2"]
with open('outputFile.csv', 'a',newline='') as csv_file:
writer = csv.writer(csv_file)
writer.writerow(rowData)
This will write CSV rows without creating additional rows!
I'm writing this answer w.r.t. to python 3, as I've initially got the same problem.
I was supposed to get data from arduino using PySerial, and write them in a .csv file. Each reading in my case ended with '\r\n', so newline was always separating each line.
In my case, newline='' option didn't work. Because it showed some error like :
with open('op.csv', 'a',newline=' ') as csv_file:
ValueError: illegal newline value: ''
So it seemed that they don't accept omission of newline here.
Seeing one of the answers here only, I mentioned line terminator in the writer object, like,
writer = csv.writer(csv_file, delimiter=' ',lineterminator='\r')
and that worked for me for skipping the extra newlines.
with open(destPath+'\\'+csvXML, 'a+') as csvFile:
writer = csv.writer(csvFile, delimiter=';', lineterminator='\r')
writer.writerows(xmlList)
The "lineterminator='\r'" permit to pass to next row, without empty row between two.
Borrowing from this answer, it seems like the cleanest solution is to use io.TextIOWrapper. I managed to solve this problem for myself as follows:
from io import TextIOWrapper
...
with open(filename, 'wb') as csvfile, TextIOWrapper(csvfile, encoding='utf-8', newline='') as wrapper:
csvwriter = csv.writer(wrapper)
for data_row in data:
csvwriter.writerow(data_row)
The above answer is not compatible with Python 2. To have compatibility, I suppose one would simply need to wrap all the writing logic in an if block:
if sys.version_info < (3,):
# Python 2 way of handling CSVs
else:
# The above logic
I used writerow
def write_csv(writer, var1, var2, var3, var4):
"""
write four variables into a csv file
"""
writer.writerow([var1, var2, var3, var4])
numbers=set([1,2,3,4,5,6,7,2,4,6,8,10,12,14,16])
rules = list(permutations(numbers, 4))
#print(rules)
selection=[]
with open("count.csv", 'w',newline='') as csvfile:
writer = csv.writer(csvfile)
for rule in rules:
number1,number2,number3,number4=rule
if ((number1+number2+number3+number4)%5==0):
#print(rule)
selection.append(rule)
write_csv(writer,number1,number2,number3,number4)
When using Python 3 the empty lines can be avoid by using the codecs module. As stated in the documentation, files are opened in binary mode so no change of the newline kwarg is necessary. I was running into the same issue recently and that worked for me:
with codecs.open( csv_file, mode='w', encoding='utf-8') as out_csv:
csv_out_file = csv.DictWriter(out_csv)
the question is that how to write string decoded from base64 to a file? I use next piece of code:
import base64
input_file = open('Input.txt', 'r')
coded_string = input_file.read()
decoded = base64.b64decode(coded_string)
output_file = open('Output.txt', 'w')
output_file.write(decoded)
output_file.close()
Input.txt contains base64 string (smth. like PD94bWwgdmVyc2lvbj0iMS4wIiBlbmNvZGluZz0iVVRGLTgiPz48cmV2aW). After script execution I suppose to see xml in Output.txt but output file contains some wrong symbols (like <?xml version="1.0" encoding="UTF-8"?><review-case create®vFFSТ#2). At the same time if I not read from base64 string from file Input.txt but specify it in script as coded_string = '''PD94bWwgdmVyc2lvbj0iMS4wIiBlbm...''' then Output.txt contains correct xml. Is this something wrong with utf encoding? How to fix this? I use Python2.7 on Windows 7. Thanks in advance.
You probably figured out, now 5 years later, but here is the solution if anyone needs it.
import base64
with open('Input.txt', 'r') as input_file:
coded_string = input_file.read()
decoded = base64.b64decode(coded_string)
with open('Output.txt', 'w', encoding="utf-8") as output_file:
output_file.write(decoded.decode("utf-8"))
under windows you open with 'rb' instead of 'r'.
in your case your code should be :
input_file = open('Input.txt', 'rb')
instead of
input_file = open('Input.txt', 'r')
btw:
http://docs.python.org/2/tutorial/inputoutput.html#reading-and-writing-files
On Windows, 'b' appended to the mode opens the file in binary mode, so there are also modes like 'rb', 'wb', and 'r+b'. Python on Windows makes a distinction between text and binary files; the end-of-line characters in text files are automatically altered slightly when data is read or written. This behind-the-scenes modification to file data is fine for ASCII text files, but it’ll corrupt binary data like that in JPEG or EXE files. Be very careful to use binary mode when reading and writing such files. On Unix, it doesn’t hurt to append a 'b' to the mode, so you can use it platform-independently for all binary files.
hope it helps
I know similar kind of question has been asked many times but seriously i have not been able to properly implement the csv writer which writes properly in csv (it shows garbage).
I am trying to use UnicodeWriter as mention in official docs .
ff = open('a.csv', 'w')
writer = UnicodeWriter(ff)
st = unicode('Displaygrößen', 'utf-8') #gives (u'Displaygr\xf6\xdfen', 'utf-8')
writer.writerow([st])
This does not give me any decoding or encoding error. But it writes the word Displaygrößen as Displaygrößen which is not good. Can any one help me what i am doing wrong here??
You are writing a file in UTF-8 format, but you don't indicate that into your csv file.
You should write the UTF-8 header at the beginning of the file. Add this:
ff = open('a.csv', 'w')
ff.write(codecs.BOM_UTF8)
And your csv file should open correctly after that with the program trying to read it.
Opening the file with codecs.open should fix it.
I did something similar to this, but couldn't find a way to write the result to an xml file.
The code on the web page you linked to uses doc.toprettyxml to create a string from the XML DOM, so you can just write that string to a file:
f = open("output.xml", "w")
try:
f.write(doc.toprettyxml(indent=" "))
finally:
f.close()
In Python 2.6 (or 2.7 I suppose, whenever it comes out), you can use the "with" statement:
with open("output.xml", "w") as f:
f.write(doc.toprettyxml(indent=" "))
This also works in Python 2.5 if you put
from __future__ import with_statement
at the beginning of the file.
coonj is kind of right, but xml.dom.ext.PrettyPrint is part of the increasingly neglected PyXML extension package. If you want to stay within the supplied-as-standard minidom, you'd say:
f= open('yourfile.xml', 'wb')
doc.writexml(f, encoding= 'utf-8')
f.close()
(Or using the ‘with’ statement as mentioned by David to make it slightly shorter. Use mode 'wb' to avoid unwanted CRLF newlines on Windows interfering with encodings like UTF-16. Because XML has its own mechanisms for handling newline interpretation, it should be treated as a binary file rather than text.)
If you don't include the ‘encoding’ argument (to either writexml or toprettyxml), it'll try to write a Unicode string direct to the file, so if there are any non-ASCII characters in it, you'll get a UnicodeEncodeError. Don't try to .encode() the results of toprettyxml yourself; for non-UTF-8 encodings this can generate non-well-formed XML.
There's no ‘writeprettyxml()’ function, but it's trivially simple to do it yourself:
with open('output.xml', 'wb') as f:
doc.writexml(f, encoding= 'utf-8', indent= ' ', newl= '\n')
f = open('yourfile.xml', 'w')
xml.dom.ext.PrettyPrint(doc, f)
f.close()